Biological Parameters

Trace elements are essential for many metabolic pathways. Furthermore, biological activity can have profound effects on the distribution and speciation of trace elements and isotopes (TEI). In order to fully understand biogeochemical cycles of TEI in the sea, it is essential to elucidate biological processes that influence the geochemistry and fate of trace elements in marine systems. This is the goal of implementing a BioGEOTRACES component of GEOTRACES.

Given the constraints in laboratory space and wire time on most global section GEOTRACES cruises, sampling efforts for biological parameters have been limited to three laboratories: Penny Chisholm (MIT), Julie LaRoche (Dalhousie University) & Gerhard Herndl (University of Vienna), and have focused on "omic" data. However, other oceanographic studies (e.g. GEOTRACES process studies) focus on specific biological processes that enhance our understanding of trace metal biogeochemical cycles. Even though these cruises do not measure all the core parameters of GEOTRACES, they normally measure at least one trace element, in addition to multiple hydrographic and biological parameters/rate processes (e.g. chlorophyll a, HPLC pigments, nutrients, PAR, flow cytometry, functional genes, primary and secondary productivity, trace metal uptake and stoichiometry). Access to these data will benefit the interpretation of TEI results.

The GEOTRACES International Data Assembly Centre (GDAC) is happy to accept biological parameters as approved by the GEOTRACES SSC. All data submitted must include a detailed methodology and comply with the strict metadata data requirements of GEOTRACES (minimum supporting metadata - event, station, lat, long, depth, bottle number). Biological data will be labeled as "not calibrated" on GDAC. The data should be submitted to Ed Mawji with sufficient ancillary data to allow interpretation of results. These include at least temperature and salinity, and, preferably, nutrients and oxygen. Collection of CTD and other data that aid in interpreting TEI data should follow GO-SHIP guidelines on how to produce good quality CTD data, at: http://www.go-ship.org/HydroMan.html